Circulation of enterovirus D68 (EV-D68) causing respiratory illness in New South Wales, Australia, between August 2018 and November 2019

The incidence of enterovirus D68 (EV-D68) in New South Wales, Australia, is unknown. As part of a state-wide surveillance program, enterovirus positive diagnostic specimens were assessed from patients presenting to hospitals with respiratory and meningitis syndromes from August 2018 to November 2019. Diagnostic enterovirus positive samples were collected from 339 patients and re-extracted followed by targeted PCR across the whole EV-D68 genome (7.4 kb). Obtained amplicons (n=208) were sequenced using Illumina sequencing technology and the phylogenetic relationships analysed relative to EV-D68 Fermon strain. We identified EV-D68 in 31 patients, both children (n=27) and adults (n=4). Phylogenetically, the majority (n=30) were from subclade B3, the same as that causing outbreaks of EV-D68 across the USA and Europe during 2018. These data strengthen the importance of having an active enterovirus surveillance network.

Using the Acute Flaccid Paralysis Surveillance System to Identify Cases of Acute Flaccid Myelitis, Australia, 2000‒2018

Since 2012, the United States has reported a distinct syndrome of acute flaccid paralysis (AFP) with anterior myelitis, predominantly in children. This polio-like syndrome was termed acute flaccid myelitis (AFM). Australia routinely conducts AFP surveillance to exclude poliomyelitis. We reviewed 915 AFP cases in Australia for children <15 years of age during 2000‒2018 and reclassified a subset to AFM by using the US Council of State and Territorial Epidemiologists case definition. We confirmed 37 AFM cases by using magnetic resonance imaging findings and 4 probable AFM cases on the basis of cerebrospinal fluid pleocytosis. Nonpolio enteroviruses were detected in 33% of AFM cases from which stool samples were tested. Average annual AFM incidence was 0.07 cases/100,000 person-years in children <15 years of age. AFM occurred sporadically in Australia before 2010 but regularly since then, indicating sustained, albeit rare, clinical manifestation in children. The AFP surveillance system in Australia is well-positioned to identify future AFM cases.

Enterovirus D68-Associated Acute Flaccid Myelitis, United States, 2020

Acute flaccid myelitis (AFM) is a serious neurologic condition that causes limb weakness or paralysis in previously healthy children. Since clusters of cases were first reported in 2014, nationwide surveillance has demonstrated sharp increases in AFM cases in the United States every 2 years, most occurring during late summer and early fall. Given this current biennial pattern, another peak AFM season is expected during fall 2020 in the United States. Scientific understanding of the etiology and the factors driving the biennial increases in AFM has advanced rapidly in the past few years, although areas of uncertainty remain. The Centers for Disease Control and Prevention and AFM partners are focused on answering key questions about AFM epidemiology and mechanisms of disease. This article summarizes the current understanding of AFM etiology and outlines priorities for surveillance and research as we prepare for a likely surge in cases in 2020.

Enterovirus A71 vaccine effectiveness in preventing enterovirus A71 infection among medically-attended hand, foot, and mouth disease cases, Beijing, China

Introduction: Enterovirus A71(EV-A71)-associated hand, foot, and mouth disease (HFMD) has been reported worldwide, and poses a particularly heavy burden on patients, families, and society in China. Three Chinese companies have licensed inactivated EV-A71 vaccines, all of which have demonstrated good efficacy for preventing EV-A71-associated disease in clinical trials. However, real-world performance of EV-A71 vaccine has not been evaluated.

Methods: We used a test-negative design case-control study to estimate vaccine effectiveness (VE) against medically attended EV-A71-associated HFMD. Subjects were children 5 years of age and under who had been in health facilities participating in the HFMD case and virologic surveillance platforms in Beijing. Enterovirus infections were laboratory confirmed, and EV-A71 vaccination status was extracted from electronic immunization records. Children testing positive for EV-A71 were cases; controls were children testing negative for EV-A71 infection. Logistic regression was used to estimate VE. We assessed sensitivity of VE estimates to control group inclusion criteria by repeating the regression analyses with two alternative control groups.

Results: A total of 2,184 HFMD patients aged 5 years and under were enrolled in the study; 24 were severe, and 2,160 were mild. For severe cases, two-dose VE estimate was 100% (95% CI: −68.1%, 100%). For mild cases, 1-dose and 2-dose adjusted VE estimates were 69.8% and 83.7%, respectively. Two-dose VE estimates varied by less than 4 percentage points regardless of control group definition.

Conclusions: Our findings suggested the vaccines performed well in the real world for children 5 years of age and under in Beijing, China.

Enterovirus D68 Infection in Children with Acute Flaccid Myelitis, Colorado, USA, 2014

Odds of this viral infection in the nasopharynx were 10 times greater for children with this condition than for controls.

During August 8, 2014–October 14, 2014, a total of 11 children with acute flaccid myelitis and distinctive neuroimaging changes were identified near Denver, Colorado, USA. A respiratory prodrome was experienced by 10, and nasopharyngeal specimens were positive for enterovirus D68 (EV-D68) for 4. To determine whether an association exists between EV-D68 infection and acute flaccid myelitis, we conducted a retrospective case–control study comparing these patients with 2 groups of outpatient control children (1 group tested for acute respiratory illness and 1 for Bordetella pertussis infection). Adjusted analyses indicated that, for children with acute flaccid myelitis, the odds of having EV-D68 infection were 10.3 times greater than for those tested for acute respiratory infection and 4.5 times greater than for those tested for B. pertussis infection. No statistical association was seen between acute flaccid myelitis and non–EV-D68 enterovirus or rhinovirus infection. These findings support an association between EV-D68 infection and acute flaccid myelitis.

First reported enterovirus D68 infection in pediatric patients from the Caribbean region: evidence of spread from the U.S. outbreak

The 2014 enterovirus D68 (EV-D68) outbreak in the United States raised concerns about the introduction of the virus in the Caribbean region. The objective of this study was to provide rapid evidence of the introduction of EV-D68 strains in the Caribbean region during the 2014 outbreak in the United States, using a relatively simple phylogenetic approach. From October 2014 to May 2015, four EV-D68 cases from two countries (Bermuda and Dominica) were detected at the regional referral laboratory at the Caribbean Public Health Agency (Port of Spain, Trinidad and Tobago) based on molecular testing of respiratory specimens. All cases were children presenting to hospitals with moderate respiratory distress. No cases of acute flaccid paralysis were detected. Phylogenetic analysis of the Caribbean strains showed more than 99% similarity with the 2014 U.S.-outbreak strain, providing evidence of the introduction and circulation of the virus in the region.